Breaker mechanism



INVENTOR JO/m W/Wag.

ATToRNE WlTN ESSES:

Patented Apr. 6, 1943 BREAKER BIECHANISM John W. May, Pittsburgh, Pa., assignor to yWeat'- o, inghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,y acci-poration o! Penn- Sylvania Application December 19, 1941, SerialNo. 423,633

4 claims. (Gazon- 115) My invention relates to circuit breakers and,

in particular, relates to mechanismsfor openingv yand reclosing circuit breakers of the trip-free type. c n f ,o f,

One object of my invention is to provide a GTI mechanism for a circuit breaker which shall be f biased to circuit-closing position. f

Another object of my invention is to Aprovide a mechanism for a circuit breaker of the trip-free type in which a single spring performs the functions of biasing the circuit breaker to circuit-closing position whenthe trip-free latch is in its normal or non-released condition, but moves the circuit breaker to circuit-,opening D- sition when the trip-free latch is released( Another object of my invention is toprovide al trip-free circuitbreaker mechanism which is normally biased to circuit-closing position which shall be extremely simple in mechanical strucy ture, cheap in first cost and adapted for ready manufacture in factory production. f

Other objects of .my invention will become apparent upon reading the followingr` description taken in connection with vthe drawing in which the single figure shows a circuit interrupter in accordance with my invention.`

One convenient fieldof use for .circuit breakr ers in accordance with my invention is as a sub.y

stitute for the circuitinterrupter ydescribed in my copending application, Serial No. 423,631, filed December 19; 1941, for an Automatic reclosextinguishing structurev 8 of a conventional typen A which forms no parto! the present invention and hence need not be more fully described here. The movable ycontact is mounted upon a resilient arm I2 supported on a link Il which turns upon a stationary pivot l nxed relative to the container` I. The free end oi the link I! is pivoted to a link Il which, in turn, is pivoted to a second 1ink'I5, the latter turning upon a pivot I6 which remains stationary relative to the container I until the circuit breaker is tripped by ing breaker, in which the circuit breaker mechanism is biased to circuit-closing position by au external spring.

Referring in detail to the drawing, an enclosing box or container I, which may be of insulaty ing material if desired, buty which'I prefer to make of metal, contains the elements of a circuit breaker of the type described in Dorfman et al. Patent N0.f2,044,1.57, issued June 16, 1936. and assigned to Westinghouse Electric & Manufacturing Company of East Pittsburgh, Pennsylvania, assignee of my present application.

Current may be conducted into the container I through the conventional conduit connections. one side of the line being connected Within the container to a stationary terminal 3 of the circuit breaker and the other side of' the line being connected to a terminal screw l within the container. The path of current through the circuit breaker is from the contact 3 to the movable contact 5, thence through a iiexible lead 6 to a terminal block 1 and the two limbs of a bimetal 2l to the terminal screw l. The contact elements 3 and 5 are housed within an arcan overload, as will later appear more fully. The pivot Ii is carried by an arm I1 which turns upon a pivot Il having a. xed support relative to the box I. The free end of the arm I 1 forms oney member of a trip-free latch, the 'other member `I9 of which is attached to the bimetal` 2| which is heated by the current'through the circuit breaker. A s long as the current through the circuit breaker does not exceed a predetermined normal value, thefree end of the arm I1 is held in stationary engagement with the latch I9. but is released from engagement there-r with upon lthe occurrence of an overload in the line through the circuit breaker. y

A circuit breaker operating arm 22 has a pivot 2! which is supported in rixed relation to the rcontainer I and extends through `a slot in the cover of the container I. The pivot 23,is posi-l tioned on the opposite side of the pivot 8 from that iny which the link Il extends in the closedcircuit position of -the circuit interrupter. A

spring is connected between a Asuitable point on the arm 22 and the bearing pin `which interconnects the links Hand I5.,k When the circuit breaker isy in fits closed circuit position, that shown in the drawing, the arm 22 is so positioned the drawing. It will be seen that the links u, ls 1 constitute a toggle tending to holdthe movable contact li into engagement with the stationary .contact 3 solong as the arm I1 is held in the position shown in the drawing by the latch member I9. When it is desired to open the cirv cuit breaker manually, the handle 22 is moved in a counterclockwisedirection about the pivot 23, thus displacing the spring 24 to such a position that it pulls the pivot pin of the toggle.

linkjir clockwise in the drawing, thereby break-v ing the toggle Il, I5 and rotating the arm I2 vabout rthe pivot 8 to open the circuit breaker.

position by spring 2l, after which spring 24 again pulls the toggle Il, I5 to the position shown inl the drawing, rotating the arm I2 about the stationary pivot 8 to close the contact l into engagement with the contact 3.

It will be observed that the spring 2l thus biases the circuit breaker to its closed circuit position and likewise biases the handle 22 to the position shown in the drawing whenever the circuit breaker is closed. Handle 22 is biased to closed position whether contacts are open or closed, unless latch ilhasreleasedarm I1.

When overload current iiows through a circui interrupter for s.v suiiicient time. bimetal 2| is deiiected enough so that the latch Il is moved so far to the left in the drawing that it slips oi!! the edgeof` the arm Il. When this occurs, the member I1 will move clockwise about its pivot I2 under the stress of the spring 24 acting on the knee of the toggle links i4, I5. The movable contact i will be rotated in a counterclockwise direction about the pivot 8 to open the circuit breaker. The cessation of current iiow through the bimetal 2| permits it to move to its original position. 'Ihe arm I1 may be relatched on I 9 by rotating handle 22 counterclockwise so that bracket 25 forces arm i1 to the left until it is slightly past the latch Il. The biasing effect of spring 24 will then pull the arm' 22 clockwise as soon as the attendant releases the handle and the circuit breaker will again be moved to its closed circuit position.

I claim as my invention:

l. In a circuit breaker, a stationary contact, a movable contact supported on a pivoted arm having its outer end connected through a linkage to a, second pivoted arm, a latch governed by a current-responsive element engaging the free end of said second pivoted arm, a third pivoted arm having a fulcrum on the opposite side of the pivot for the iirst-mentioned pivoted arm than that toward which said rst pivoted arm extends, and a bias means interconnecting a point on said linkage with a point on said third pivoted arm.

2. In a circuit breaker, a stationary contact, a movable contact supported on a pivoted arm hav.- ing its outer end pivoted to a link which is connected by a second link to a second pivoted arm, a latch responsive to current flow through said contacts adapted to maintain said second pivoted arm stationary during normal cun'ent iiow through said contacts, but to release said second pivoted arm for rotation about its pivot under predetermined overload conditions of the current through said contacts, a third pivoted arm having a fulcrum positioned on the opposite side of its stationary pivot from the rst-mentioned pivoted arm, and bias means interconnecting a point on said third pivoted arm to the pivot connecting the two said links, the position of said point on said third pivoted arm being such that said bias means constrains said separable contacts to circuit-closing position when the second pivoted arm is restrained by said latch and said third pivoted arm is in one of its extreme positions, but said bias means urges said separable contacts to opencircuit position when said second pivoted arm is released by said latch.

3. In a circuit breaker, a stationary contact, a

' movable contact supported on a pivoted arm having its outer end pivoted to a link which is connected by a second link to a second pivoted arm, a latch responsive to current now through nid contacts adapted to maintain said second pivoted I a iulcrum positioned on the opposite side of its stationary pivot from the tiret-mentioned pivoted arm, and bias means interconnecting a point on said third pivoted arm to the pivot connecting the two said links', the position of said point on said third pivoted ann being such that said bias means constrains said separable contacts to circuit-closing position when the second pivoted arm is restrained by said latch and said third pivoted arm is in one of its extreme positions, but said bias means urges said separable contacts to opencircuit position when said second pivoted arm is released by said latch,l said bias means exerting a greater stress between its terminals when said third pivoted arm is moved to its circuit-opening position than when said third pivoted arm and said first pivoted arm are in their circuit-opening position.

4. In a circuit interrupter, a pair oi' separable contacts, a mechanism adapted to move said contacts from circuit-opening to circuit-closing position. a pivoted handle adapted in one extreme position to move said separable contacts to circuit-closing position and in its opposite extreme position to move said separable contacts to circuit-opening position, a bias means interconnecting said handle with said mechanism and acting in the circuit-opening position of said handle to urge said separable contacts to circuit-opening position, a trip-free arm provided with a current-responsive latch and adapted when in latched position to cooperate with said bias means to maintain said separable contacts closed when said handle is in its circuit-closing position, but to permit said bias means to move said separable contacts to circuit-opening positionfwhen it is unlatched, the pivot of said handle being so positioned that said bias means is more strongly stressed if said separable contacts are in circuitclosing position and said handle is in its circuitopening position than if said handle were in its circuit-closing position.

JOHN W. MAY, 

